Arizona weekly enterprise., 1887-11-26
THE THEORY OF STORMS.
An Easily Understood Description or How They Originate and Pass Away.

An Easily Understood Description or
 How They Originate and Pass Away.
 Sergt. E. B. Dunn, the signal service officer in charge of the station on the Equitable building, thus explained the theory of storms the other day:
 ssStorms are caused" he said, "first by the meeting and commingling of in- equal atmospheric temperatures or pres s,lres; second, by the rotation of the | earth, and, thirdly, by unequal specific gravity of different layers of air. The first of these causes is the prime one; the other two are but of secondary and con- paratively slight importance in the gen. eration of storm.
 sIt is a well known fact that warm air rises. It is equally well known that the earth becomes heated by the suns rays falling upon it, and by the absorption and radiation of this stored up heat renders the temperature higher at the surface than at elevated points. For time thls
 hot air on the surface is kept down by
 atmospheric pressure, but there comes
 time when the expansion becomes so great as to break through the cold air pressure, and the hot air goes up with | rush, rising sometimes to great helght. | As this warm air rises it creates vacuum | below. and the cooler air rushes in from
 all sides to fill its place. This cool air, as
 it gets gradually heated, also rises, and
 more cool air rushes in to again fill the
 vacuum. Right at tlHs point where the | hot air first rises Is the center of storm
 Yhe vacuum caused by the ascending hot
 air sucks intos its vortex the air from
 every point of the compass, and this suc-
 ton causes wind, but places affected by
 a storm thus formed, it will be seen, will
 have the wind from different points of
 the compass, according to their dlrec-
 ton from the storm center. Thus,
 locality directly south of storm center
 will have the wind from the south, as 1t rushes north. When this warm air has accumulated at a sufficiently high altl- tude. and become surrounded by a cooler { air. the moisture in it begins to condense, forming rain.
 ssThe rushing in of the cool air to fill the vacuum caused by the rising hot air g gives motion to the accumulation oi
 warm air, and it begins to whlrl about n in a circle, but at the center all IS calm
 and clear. Thus it is that sometimes wt f experience a lull in the storm, as 1t I Q called. Such a brief respite is nothing q more than the passing of storm center
 directly over head, through which thu # sun even may shine unobstructedly. IF "As this storm keeps whirling abou " over head it continues to gather energy V, and grows by the accession of more heate' y air, exactly as snowfall is increased i ;;t diameter by rolling it in the snow. A ~ last the accumulation becomes of sue " proportions as to feel the effects of tn .He H earth's rotation, and it begins to move s' This rotation of the earth, being fror y west to east, gives all the storms of an It extent the same general direction. Sue " general direction, however, from west is east. is liable to Reflections from var1ol ei causes, such as mountains, conditions
 the atmosphere, by coming in conta
 with other storms or air currents, al
 by large areas of water.
 ssNine out of ten American storn es originate in the mountainous regions II, the northwest, where the warm air " the valleys rises and comes in conta It with the cool air from the great eley w tions of the Rocky mountains. The er- storms take generally southeasterly { ere rection until they get into the dry reg1o Tas of Kansas, and there, becoming fal ms isheo, as it were, for want of moistul
 
 and as if scenting the water for whi yer they long from the direction of the grt at lake region, they make turn to the northeast and proceed to the great lak ch- where they absorb abundance of moistu ing and then travel on east, deluging us W ill. this water from the lakes. All such g eral storms pass out from this country lou the Atlantic, through the St. Lawrel ing valley. Within recent years these Anne and can storms have been actually tra' cry across the Atlantic to Europe, and so d a of them even as far as Asia.
 our "All storms originate in the same W ile. whether on land or at sea; in summer ave in winter. The undercurrent of vou which rises need not necessarily be wa Joe. to make it rise; as, for instance, WI ,ow the temperature is below the freez we point; but the undercurrent must b' | to a higher temperature than that ab ns a and surrounding it to force it to rise. heir other words, storm is originated b , of commingling of unequal atmosph ha temperatures. ''-New York Commer nave Advertiser.